Follow full and compressed timestamps
FIT can store full timestamps and compact timestamp headers. The latter depend on a preceding full timestamp anchor and a five-bit offset with rollover. This desk decodes that sequence rather than treating every compact header as an independent absolute time. A missing anchor is a parsing failure, not permission to assume a date.
Decoded times are shown in UTC. Repeated or backward record times appear as consistency findings. A valid CRC does not rule these out because the device may have written them intentionally or while its clock was changing. Interpret the findings in the context of the device and activity rather than automatically replacing them with evenly spaced samples.
Retain fields that are not projected
The FIT protocol allows developer-defined fields alongside the native profile. Decoding all of their semantics requires their descriptions and producer-specific knowledge. This desk respects their declared byte lengths and preserves their bytes in the recovered prefix, while clearly excluding them from the narrow standard CSV/GPX projection.
Likewise, an unknown native field is not automatically an error. It may belong to a newer profile or a device-specific feature. Retaining complete message bytes avoids dropping that evidence. An unsupported scalar or array field is not guessed into a column with an invented unit. The report states exactly which standard fields the projection can expose.
Review summaries and gaps
The audit compares required summary fields, elapsed and timer ordering, and reported session counts where present. It also flags decreasing distance counters and coordinates outside geographic bounds. These checks catch useful classes of problems but do not establish calibration, sport interpretation or platform compatibility.
A recovered track can remain valuable even when its final activity summary is missing. Treat it as a partial record and preserve that status in the files you share. When the missing bytes are still on the device, a fresh transfer or the manufacturer’s recovery workflow may recover more than any browser tool can reconstruct from a truncated copy.